Plate cutting device for fireproof door and using method of plate cutting device

The plate cutting device for the fireproof door relates to the technical field of fireproof door production and comprises a workbench, a feeding table is arranged on one side of the outer wall of the top of the workbench, a working box is arranged on the other side of the outer wall of the top of the workbench, one end of the feeding table extends into the working box, and the other end of the feeding table extends into the working box. A feeding mechanism is arranged at the top of the feeding table, a motor is arranged on one side of the outer wall of the top of the working box, an output shaft of the motor is connected with a lead screw, the outer wall of the lead screw is sleeved with a moving plate, the moving plate is in sliding fit with the inner wall of one side of the working box, and an extrusion mechanism is arranged at the bottom end of the moving plate. An electric control sliding rail is arranged in the middle of the inner wall of the top of the working box, a sliding block is slidably connected